Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Richner-Hanhart syndrome corresponds to a tyrosine elevation in serum due to a defect in soluble tyrosine amino-transferase in liver cells. This new enzymopathy which is transmitted in an autosomal recessive mode is called oculo-cutaneous tyrosinosis. It is curable by a low diet in tyrosine and its precursors. The diagnosis has been clinically suggested in an 18 months old girl, by the association of punctate palmar and plantar keratosis, dendritic ulcerated keratitis, and mental retardation. The diagnosis was established by elevation of tyrosinemia up to 52 mg/100 ml associated with a high urinary elimination of tyrosine and phenylcetonic acid. Absence of anomaly in the metabolism of methionin and hepatorenal lesion is characteristic. The diagnosis was confirmed by the absence of soluble tyrosine aminotransferase in liver cells and by the effectiveness of the diet. The clinical keratosis corresponds histologically to a orthokeratotic hyperkeratosis. The keratinocytes show 2 types of anomalies ranged in the epiderm. Intracytoplasmic vacuoles which include or lead to pseudomyelinic formations extend progressively from the mitochondrial alterations in the epidemial basal layers. Bulky polyhedral electron dense particles are found in the cytoplasm of the superficial keratinocytes. Most of these images have been demonstrates anteriorly in the keratinocytes ant the corned; on the other hand, signs of mitochondrial anomaly had not been observed. The genesis of these cellular alterations based on the liberation of lysosomial enzymes by the action of crystals of tyrosine has been suggested by Goldsmith from experimental facts. However, it seems that the mitochondrial defect occurs outside this mechanism.
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PMID:[Changes in the keratinocytes in oculo-cutaneous tyrosinosis: Richner-Hanhart syndrome (author's transl)]. 723 83

Richner-Hanhart syndrome (Tyrosinemia Type II) is an autosomal recessive disorder of amino acid metabolism characterized by ocular changes, painful palmoplantar hyperkeratosis, and mental retardation. Serum tyrosine increases due to tyrosine aminotransferase deficiency resulting in the deposition of tyrosine crystals in the cornea and in corneal inflammation. Patients are often misdiagnosed as having herpes simplex keratitis. We report on a child who presented with bilateral keratitis secondary to Tyrosinemia Type II diagnosed as herpes simplex keratitis.
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PMID:Richner-Hanhart syndrome (tyrosinemia type II). Case report and literature review. 764 39

Tyrosinemia type II (Richner-Hanhart syndrome, RHS) is a disorder of autosomal recessive inheritance characterized by keratitis, palmoplantar hyperkeratosis, mental retardation, and elevated blood tyrosine levels. The disease results from deficiency in hepatic tyrosine aminotransferase (TAT). We have previously described one deletion and six different point mutations in four RHS patients. We have now analyzed the TAT genes in a further seven unrelated RHS families from Italy, France, the United Kingdom, and the United States. We have established PCR conditions for the amplification of all twelve TAT exons and have screened the products for mutations by direct sequence analysis or by first performing single-strand conformation polymorphism analysis. We have thus identified the presumably pathological mutations in eight RHS alleles, including two nonsense mutations (R57X, E411X) and four amino acid substitutions (R119W, L201R, R433Q, R433W). Only the R57X mutation, which was found in one Scottish and two Italian families, has been previously reported in another Italian family. Haplotype analysis indicates that this mutation, which involves a CpG dinucleotide hot spot, has a common origin in the three Italian families but arose independently in the Scottish family. Two polymorphisms have also been detected, viz., a protein polymorphism, P15S, and a silent substitution S103S (TCG-->TCA). Expression of R433Q and R433W demonstrate reduced activity of the mutant proteins. In all, twelve different TAT gene mutations have now been identified in tyrosinemia type II.
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PMID:Novel and recurrent tyrosine aminotransferase gene mutations in tyrosinemia type II. 954 43

Tyrosinemia type II or Richner-Hanhart Syndrome (RHS) is an autosomal recessive disorder characterized by keratitis, palmoplantar keratosis, mental retardation, and elevated blood tyrosine levels. The disease is due to a deficiency of hepatic cytosolic tyrosine aminotransferase (TATc), an enzyme involved in the tyrosine catabolic pathway. Because of the high rate of consanguinity this disorder seems to be relatively common among the Arab and Mediterranean populations. RHS is characterized by inter and intrafamilial phenotypic variability. A large spectrum of mutations within TATc gene has been shown to be responsible for RHS. In the present study, we report the clinical features and the molecular investigation of RHS in three unrelated consanguineous Tunisian families including 7 patients with confirmed biochemical diagnosis of tyrosinemia type II. Mutation analyses were performed and two novel missense mutations were identified (C151Y) and (L273P) within exon 5 and exon 8, respectively. The 3D-structural characterization of these mutations provides evidence of defective folding of the mutant proteins, and likely alteration of the enzymatic activity. Phenotype variability was observed even among individuals sharing the same pathogenic mutation.
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PMID:Clinical and mutational investigations of tyrosinemia type II in Northern Tunisia: identification and structural characterization of two novel TAT mutations. 1657 53

Bilateral pseudo-dendritic keratitis in infancy can be due to tyrosinemia, a rare metabolic disorder. Ocular involvement may be the earliest presenting manifestation of this disease. Early diagnosis is essential because dietary modifications can result in complete reversal of the manifestations of this disorder. This disease must be suspected in all cases of non-responsive dendritic keratitis in the pediatric age group, especially if it is associated with cutaneous lesions such as patmoplantar keratosis. Serum tyrosine levels must be done in these cases.
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PMID:Unusual dendritic keratitis. 1718 89

Richner-Hanhart syndrome or oculocutaneous tyrosinemia is characterized by painful palmo-plantar keratoderma, keratitis with photophobia and progressive mental impairment. The syndrome is caused by deficient hepatic tyrosine aminotransferase and is inherited as an autosomal recessive trait. We report a 28 year-old woman with lifelong photophobia, eye pain and painful plantar hyperkeratotic lesions, necessitating use of a wheelchair. A few days after instituting tyrosine lowering therapy, her eye symptoms disappeared and she could walk without pain. Her brother was later diagnosed with the same disease.
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PMID:[Two cases of Richner-Hanhart syndrome (oculocutaneous tyrosinemia)]. 1836 60

Schnyder corneal dystrophy (SCD) is a rare corneal dystrophy characterized by abnormally increased deposition of cholesterol and phospholipids in the cornea leading to progressive vision loss. SCD is inherited as an autosomal dominant trait with high penetrance and has been mapped to the UBIAD1 gene on chromosome 1p36.3. Although 2/3 of SCD patients also have systemic hypercholesterolemia, the incidence of hypercholesterolemia is also increased in unaffected members of SCD pedigrees. Consequently, SCD is thought to result from a local metabolic defect in the cornea. The corneal findings in SCD are very predictable depending on the age of the individual, with initial central corneal haze and/or crystals, subsequent appearance of arcus lipoides in the third decade and formation of midperipheral haze in the late fourth decade. Because only 50% of affected patients have corneal crystals, the International Committee for Classification of Corneal Dystrophies recently changed the original name of this dystrophy from Schnyder crystalline corneal dystrophy to Schnyder corneal dystrophy. Diagnosis of affected individuals without crystalline deposits is often delayed and these individuals are frequently misdiagnosed. The differential diagnosis of the SCD patient includes other diseases with crystalline deposits such as cystinosis, tyrosinemia, Bietti crystalline dystrophy, hyperuricemia/gout, multiple myeloma, monoclonal gammopathy, infectious crystalline keratopathy, and Dieffenbachia keratitis. Depositions from drugs such as gold in chrysiasis, chlorpromazine, chloroquine, and clofazamine can also result in corneal deposits and are different from SCD. Diseases of systemic lipid metabolism that cause corneal opacification, such as lecithin-cholesterol acyltransferase deficiency, fish eye disease and Tangier disease, should also be considered although these are autosomal recessive disorders.
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PMID:Differential diagnosis of Schnyder corneal dystrophy. 2154 Jun 32

Fifteen-month-old twins presented with photophobia and bilateral corneal pseudodendrites, and tyrosinemia type II was suspected. Plasma tyrosine levels were elevated. After therapy with tyrosine-restricted diet, corneal lesions resolved. Bilateral pseudodendritic keratitis may be the initial or only manifestation of tyrosinemia type II.
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PMID:Isolated corneal pseudodendrites as the initial manifestation of tyrosinemia type II in monozygotic twins. 2258 28

Tyrosinemia type II, also designated as oculocutaneous tyrosinemia or Richner-Hanhart syndrome (RHS), is a very rare autosomal recessive disorder. In the present study, we report clinical features and molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in two young patients, both born to consanguineous unions between first-degree cousins. These two unrelated families originated from Northern and Southern Tunisia. The clinical diagnosis was based on the observation of several complications related to Richner-Hanhart syndrome: recurrent eye redness, tearing and burning pain, photophobia, bilateral pseudodendritic keratitis, an erythematous and painful focal palmo-plantar hyperkeratosis and a mild delay of mental development. The diagnosis was confirmed by biochemical analysis. Sequencing of the TAT gene revealed the presence of a previously reported missense mutation (c.452G>A, p.Cys151Tyr) in a Tunisian family, and a novel G duplication (c.869dupG, p.Trp291Leufs 6). Early diagnosis of RHS and protein-restricted diet are crucial to reduce the risk and the severity of long-term complications of hypertyrosinemia such as intellectual disability.
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PMID:Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner-Hanhart syndrome. 2395 27

Richner-Hanhart syndrome (RHS, tyrosinemia type II) is a rare, autosomal recessive inborn error of tyrosine metabolism caused by tyrosine aminotransferase deficiency. It is characterized by photophobia due to keratitis, painful palmoplantar hyperkeratosis, variable mental retardation, and elevated serum tyrosine levels. Patients are often misdiagnosed with herpes simplex keratitis. We report on a a boy from Brazil who presented with bilateral keratitis secondary to RHS, which had earlier been misdiagnosed as herpes simplex keratitis.
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PMID:Herpetiform keratitis and palmoplantar hyperkeratosis: warning signs for Richner-Hanhart syndrome. 2783 14


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